UVA 1658 Admiral "minimum cost maximum Flow"

Split, each point split into I,i '.

Between I and I ' a cost of 0, the capacity of 1 side, you can guarantee that each point only once

Special points, between 1 and N,, between N and 2*n a cost of 0, 2 of the edge, you can find two paths

1#include <cstdio>2#include <cstring>3#include <cmath>4#include <iostream>5#include <algorithm>6#include <Set>7#include <map>8#include <stack>9#include <vector>Ten#include <queue> One#include <string> A using namespacestd; -  -typedefLong LongLL; the Const intMAXN = the; - Const intINF = (1<< -) -1; -   - intfirst[maxn],vis[maxn],dis[maxn],pos[maxn],ecnt,size; +  - structedge{ +     intV,next,cap,cost; A} e[Ten*MAXN]; at  - voidinit () { -ECNT =0; -memset (first,-1,sizeof(first)); - } -    in voidAdd_edge (intUintVintCapintCost ) { -E[ECNT].V =v; toE[ecnt].cap =cap; +E[ecnt].cost =Cost ; -E[ecnt].next =First[u]; theFirst[u] = ecnt++; *      $E[ECNT].V =u;Panax NotoginsengE[ecnt].cap =0; -E[ecnt].cost =-Cost ; theE[ecnt].next =First[v]; +FIRST[V] = ecnt++; A } the    + BOOLSPFA (intSintt) - { $     intu,v,i; $Queue <int>Q; -memset (Vis,0,sizeof(Vis)); -      for(i=0; I <= size;i++) dis[i]=INF; the      -dis[s]=0;Wuyivis[s]=1; the Q.push (s); -      Wu      while(!Q.empty ()) { -U=q.front (); Q.pop (); vis[u]=0; About          for(i = first[u]; ~i;i =E[i].next) { $v=e[i].v; -                if(E[i].cap >0&& Dis[u]+e[i].cost <Dis[v]) { -dis[v]=dis[u]+E[i].cost; -pos[v]=i; A                   if(!Vis[v]) { +vis[v]=1; the Q.push (v); -                   } $                } the           } the     } the     returnDIS[T]! =INF; the } -  inLL MCMF (intSintt) the { the     inti; AboutLL cost=0, flow=0; the      while(SPFA (s,t)) { the         intD=INF; the          for(i = t;i! = S;i = e[pos[i]^1].v) { +D =min (d,e[pos[i]].cap); -         } the          for(i = t;i! = S;i = e[pos[i]^1].v) {BayiE[pos[i]].cap-=D; thee[pos[i]^1].cap + =D; the         } -Flow + =D; -Cost + = dis[t]*D; the     } the     returnCost ; the } the  -  the intMain () { the     intn,m; the      while(SCANF ("%d%d", &n,&m)! =EOF) {94 init (); theSize =2*n+1; theAdd_edge (1,1+n,2,0); theAdd_edge (N,2*n,2,0);98          for(inti =2; i < n;i++) Add_edge (I,i+n,1,0); About          -          for(inti =0; I < m;i++){101             intu,v,w;102scanf" %d%d%d",&u,&v,&W);103Add_edge (U+n,v,1, W);104         } theprintf"%lld\n", MCMF (1,2*n));106     }107     return 0;108}

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UVA 1658 Admiral "minimum cost maximum Flow"